Self-aligning slip ring capsule

ABSTRACT

A self-aligning rotary electrical contact assembly for concentric relatively rotatable members having an annular recess in the first member, a linear recess in the second member, the linear recess being transverse to the annular recess, a first electrical conductor disposed within the annular recess forming an arcuate conducting element, a second electrical conductor linearly disposed within the linear recess, and a brush member disposed in the annular recess having a portion thereof projecting into the linear recess wherein the brush member is in rotatable contact with the arcuate conducting element and is in slidable contact with the second electrical conductor, thereby causing the brush member to be automatically positioned.

United States Patent 51 Mar. 28, 1972 Brigg [54] SELF-ALIGNING SLIP RINGCAPSULE [72] Inventor: Kenly C. Bugg, Fort Wayne, Ind.

[73] Assignee: Kendlck Manufacturing Company, Fort Wayne, Ind

[22] Filed: Feb. 11, 1970 [2]] Appl. No.: 10,500

[52] US. Cl ..339/8 [51] Int. Cl ..H0lr 39/40 [58] Field of Search..339/7, 9, 5, 8; 310/249, 242, 310/248 [56] References Cited UNITEDSTATES PATENTS 2,843,830 7/1958 Blanding ..339/5 M 3,389,366 6/1968Galles ..339/7 R Primary Examiner-Richard E. Moore Attorney-Hume,Clement, Hume & Lee

[57] ABSTRACT A self-aligning rotary electrical contact assembly forconcentric relatively rotatable members having an annular recess in thefirst member, a linear recess in the second member, the linear recessbeing transverse to the annular recess, a first electrical conductordisposed within the annular recess forming an arcuate conductingelement, a second electrical conductor linearly disposed within thelinear recess, and a brush member disposed in the annular recess havinga portion thereof projecting into the linear recess wherein the brushmember is in rotatable contact with the arcuate conducting element andis-in slidable contact with the second electrical conductor, therebycausing the brush member to be automati cally positioned.

20 Claims, 11 Drawing Figures PATENTEDMARZFB 1972 552.971

SHEET 1 OF 4 ill IHIIIIIIII IIHIJHIII I W/m5 [/m/wf/fw f/zzPATENTEDMAR28 I972 3.652871 sum 2 [IF 4 PATENTEnuARzs 1972 SHEET 3 [IF 4PATENTEDMAR28|912 3.652.971

sum u [If 4 BACKGROUND OF THE INVENTION The present invention relates torotary electrical contact assemblies such as slip rings and selectorswitches and more particularly to a self-aligning rotary contactassembly construction known as a capsule assembly, particularly usefulin environments in which there is a demand for a highly accurate,reliable electrical connection between rotating and stationary elements.

Electromechanical control systems have achieved a high degree ofdevelopment and their use in computers, space vehicles and similarinstallations, has created a demand for highly accurate and reliableelectrical slip ring and switching assemblies. At the same time, thereis a growing demand for such assemblies that are miniaturized" andencapsulated" in the sense that all of the parts are of a minimum size,and the delicate parts are all well protected. One type of apparatuswhich fulfills this need is disclosed in a United States Patentapplication filed by Kenly C. Bugg, Ser. No. 829,526, which was filed onJune 2, I969, and was assigned to the Kendick Manufacturing Company.Although this device has served the purpose, difficulty has beenexperienced in assembling the capsule. It has heretofore been necessaryto maintain appropriate tolerances between the slots in the rotor andthe slots in the stator. These close tolerances are necessary to insureproper alignment between the rotor and stator. For example, in the abovementioned application there is normally a 0.015 to 0.012 of an inch gapbetween pitches in the assembly and, therefore, alignment tolerances arenecessarily quite small. Lastly, assembly and alignment of the brushesbetween the rotor and stator has also proved difficult. The presentinvention overcomes these limitations.

SUMMARY OF THE INVENTION The general purpose of this invention is toprovide a selfaligning rotary electrical contact assembly which embracesall of the advantages of similarly employed assemblies and possessesnone of the aforedescribed limitations. To attain this, the presentinvention contamplates an assembly including a cylindrical core member,a housing member concentrically disposed in rotatable relation aroundthe core member, an annular recess in the core member, a longitudinalrecess in the housing member, the longitudinal recess being transverseto the annular recess, a first electrical conductor disposed within theannular recess forming an arcuate conducting element, a secondelectrical conductor longitudinally disposed within the longitudinalrecess, and a brush member disposed in the annular recess having aportion thereof projecting into the longitudinal recess wherein thebrush member is in rotatable contact with the arcuate conducting elementand is in slidable contact with the second electrical conductor, therebycausing the brush member to be automatically positioned in a planeperpendicular to the axis of the core member.

It is, therefore, an object of the present invention to provide a rotarycontact assembly having a simplified construction which readily permitsminiaturization and encapsulation.

Another object is to provide a rotary contact assembly which is easy toassemble and which eliminates the difficult requirement of maintainingtolerances between the slots in the rotor and the slots in the stator.

A further object is to provide a rotary contact assembly havingself-aligning brushes.

Still another object is to provide a rotary contact assembly having aconstruction such that the component parts thereof can be formulated ofa suitable material having a low coefficient of friction so that thedevice may be made without bearings, needs no lubricant, and has verygood dielectric properties and thermal stability.

Yet another object is the provision of a rotary contact as-- semblyhaving a construction such that the brush element thereof perform thefunction of bearing members, which characteristic helps to eliminate theneed for conventional bearings and lubricants.

A still further object is to provide a rotary contact assembly which canbe fabricated without requiring hand operations of a delicate nature,and in which the components forming the rotary electrical contacts canbe given a predetermined amount of loading provided by the self-aligningbrushes.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation, partly insection, of a slip ring capsule assembly incorporating one form of theinvention.

FIG. 2 is a section taken on the lines 2-2 of FIG. I.

FIG. 3 is an end view of the apparatus shown in FIG. 1, with a portionof the cover removed.

FIG. 4 is an end view of the apparatus shown in FIG. 1.

FIG. 5 is a side elevation of the cylindrical core member for the slipring capsule assembly shown in FIG. 1.

FIG. 6 is an alternative embodiment of a portion of the apparatus shownin FIG. 1.

FIG. 7 is an end view of the alternative embodiment shown in FIG. 6.

FIG. 8 is an alternative embodiment of the brush assembly shown in FIG.2.

FIG. 9 is another alternative embodiment of the brush assembly shown inFIG. 2.

FIG. 10 is still another alternative embodiment of the brush assemblyshown in FIG. 2.

FIG. 11 is an alternative embodiment of the assembly shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawingswherein like reference characters designate like or corresponding partsthroughout the several views, there is shown in FIGS. l-S, aself-aligning rotary electrical contact assembly 10, the specific formbeing that of a slip ring capsule assembly. A substantially cylindricalhousing member 12 is provided with a plurality of spaced longitudinalgrooves or recesses 14 on the interior surface thereof. A core member 16is also provided having an area of reduced diameter 18 that is rotatablyreceived within a central longitudinal bore 20 in the housing member 12.The core member 16 is provided with a collar portion 22 of increaseddiameter against which one end 24 of the housing member 12 is adapted toabut. A suitable spacing member 26 such as a washer may be interposedbetween the collar portion 22 and the end 24 of the housing member 12provide a better fit. The housing member 12 is retained in this positionon the core member by a suitable retaining ring 28 adapted to bereceived in an annular groove 30 of a second area of reduced diameter 19of the core member 16. Suitable spacing members 32 may be providedbetween the retaining ring 28 and an outer end 34 of the housing member12. With such a construction, the housing member 12 and the core member16 are disposed in concentric, rotatable relation.

The housing member 12 and the core member 16 may be formed of a suitableplastic material, such as Teflon, for example. A material like Teflonhas proven to be particularly advantageous for a number of reasons,among which is the fact that the necessity for providing bearings iseliminated, because of the low coefficient of friction of the material.This in turn eliminates the need for any lubricant. In addition, Teflonhas very good dielectric properties and has excellent thermal stability.Although Teflon has been indicated as being a preferred material fromwhich to formulate the devices incorporating the invention, it is givenonly by way of example, and it is obvious that any material having gooddielectric properties can be utilized.

Referring again to FIGS. 1-5 it can be seen that the core member 16 hasa plurality of annular recesses 36 formed on the outer surface of thearea of reduced diameter 18. Each annular recess 36 is adapted toreceive an electrical conductor which is disposed within the annularrecess 36 to form an arcuate conducting element 38, better known as aslip ring. The two ends of each electrical conductor 38 may be threadedthrough a suitable opening 40 located in each annular recess 36, whichopening communicates with the hollow interior &2 of the core member 16.The two ends of each electrical conductor 38 extending intocommunication with the hollow interior 42 of the core member 16 aretwisted together therein to form a single lead 441 which is preferablybrought out of the end 416 of the core member 16 in a suitable manner.An additional cover plate 438 is provided to be placed over the openingin the end of the core 46 through which the leads 44 extend. Cover plate43 is installed when the full assembly of the rotary electrical contactassembly is completed and serves to protect the core leads 44.

Referring now particularly to FIGURES l, 2 and 4, the housing member 12contains a plurality of spaced longitudinal grooves or recesses 14 alongits inner surface. Each longitudinal recess 14 is provided with anelectrical conductor 50 disposed therein. One end of the electricalconductor 50 may be threaded through an aperture 52 in the housingmember l2. This first end is then joined with the second end of theelectrical conductor 50 and are twisted together externally from thehousing to form a single lead 54. The twisting of the two ends of theelectrical conductor 50 secure this conductor within the longitudinalrecess M. The leads 54 may then be collected at the end 34 of thehousing member 112 as shown in FIGURE 4. FIGS. 6 and 7 disclose analternative method of securing the longitudinal conductor 50 within thelongitudinal groove or recess 14. Rather than providing an aperturewithin the housing such as shown in FIG. 1, a plurality of recessedgrooves 56 are provided along the outer surface of the housing member12'. The two ends of each longitudinal electrical conductor 50 arethreaded through the recess 14 as well as the recess 56 and are twistedtogether in recess 56 to form a single lead 54'. It will be recognizedthat either method of securing longitudinal conductor 50 within therecess 14 may be utilized and with any of the brush members which willbe described below.

It can be seen by referring to FIGS. 1-5 that longitudinal conductors 50extend the full length of the housing member 12 and are transverse tothe arcuate conductors 38 on the core member 16. This arrangementpermits a brush member 58 to be inserted in the appropriate recess 36 ofthe core member 16 before the housing member 12 is slipped over thatportion of the core member 116. Brush member 58 is designed such thatwhen disposed in the annular recess 36 it has a portion or end 60thereof projecting into the longitudinal recess 14 of the housing member12. In this manner, the brush member 58 rotatably contacts the arcuateconductor 38 within the annular recess 36 of the core member andslidably contacts the longitudinal conductor 50 located within thelongitudinal recess 14.

Thus, to assemble the self-aligning slip ring capsule, the end 61) ofthe brush member 58 is inserted in a preselected recess 14 in thehousing member 12 and is also inserted in the annular recess 36 closestto the reduced diameter area 119 of the core member 16. As the housing12 is moved gradually into rotatable relation around the core member 16,the brush member slides along the longitudinal conductor Si) disposed inthe longitudinal recess 14. As the relative position of the core member16 and the housing member 12 is changed during this assembly operation,the upper ends 60 of the brush members 58 slide along their respectivelongitudinal conductors 50. The end result is that after the capsule iscompletely assembled, the brush members 58 have a position determined bythe annular recesses 36 in the core member 16 in which they are insertedand the electrical connection with the brush assembly 58 isautomatically established by the abutting relationship of the end 60 ofthe brush assembly 58 with the longitudinal conductor 50. This type ofconstruction permits the brush members 58 to be self-aligning since theyhave a configuration such that the annular recess 36 in the core member16 will keep them oriented in a plane perpendicular to the axis of thecore member B6.

In a preferred embodiment, the brush members 58, during the assemblyoperation, are placed so that each succeeding brush member is orientedapproximately from the preceding brush member. This orientation isaccomplished by preselecting longitudinal recesses 14 which are spacedapproximately 90 apart and then inserting the end 60 of the brushassembly 58 into these preselected recesses M. This arrangement isdesirable in that it insures that the ends as of the brush members 58,which protrude above the recesses 305 in the core member 16 into contactwith the longitudinal conductors $0, are separated a maximum distancefrom each other. Thus, an easy method of assembling a slip ring capsuleis provided. Moreover, it is no longer necessary to maintain stricttolerances between slots in the core and slots in the housing as hasbeen the requirement in the previous slip ring capsules.

Obviously, many shapes of brush members may be utilized. FIG. 2 shows apreferred brush member 58. The brush member 58 includes a first end 60which is designed to protrude beyond the periphery of the annular recess36 in the core member 16 and to protrude into the longitudinal recess 14and come in slidable contact with the conductor 51]? associatedtherewith. A bent segment 62 is provided in the brush member 58. Thebent segment 62 rotatably contacts the arcuate electrical conductor orslip ring 38. In the preferred embodiment, the brush members 58 aregiven a configuration such that they are somewhat compressed when intheir assembled position as shown in FIGURE 2 and thus provide astandardized load on the core member to. It can be seen that the bentsegment may be so designed so as to tangentially contact the arcuateconductor 38 and thus provide nearly frictionless rotatable contact.

In order to eliminate the need for any bearings, Teflon is utilized formost of the working parts. The longitudinal conductors 50 in thepreferred embodiment may be made of any suitable wire that is highlycorrosion resistant. The brush members 58 may be made from a wire knownas paliney No. 7 (heat-treated)" manufactured by the Ney Company. Theslip ring or arcuate conductor 38 may be manufactured from a wire whichis also manufactured by the Ney Company and is identified as Ney No. 69which is an alloy composed of 6 percent platinum, 69 percent gold and 25percent silver. The term wire" or conductor in this disclosure isutilized to include the conventional wire of circular cross section, aswell as other configurations such as triangular, square, rectangular orthe like, and it will be recognized by one skilled in the art that theabove wires which have been described are merely a preferred compositionand any similar electrical conducting material may be utilized.

The operation of the self-aligning rotary contact assembly 10 justdescribed is obvious from the description which has already been givenin that the arcuate conductor 33 in each annular recess 36 in the coremember 116 forms a slip ring to which an electrical connection can bemade through the lead 44, and the brush member 58 protruding into thelongitudinal recess 14 in the housing member 12 is in sliding electricalcontact with its associated longitudinal conductor 50 and is inrotatable electrical contact with the associated slip ring or arcuateconductor 38. Thus, an electrical connection is made by the brush member58 to the lead 54 and this electrical connection can be maintainedbetween the leads to associated slip ring and brush assemblies duringthe relative rotation of the housing member 12 and the core member l6.Needless to say, the rotation referred to can be established by relativemovement between the two members 12 and 116 so that either member canfunction as the rotor, although in the embodiment shown the core member16 is designed to be the rotor.

Obviously, many modifications of the brush member 53 may be made withoutdeparting from the spirit and the scope of the invention. FIGS. 8-10disclose several variations in the shape of the brush assembly member 58and any of these variations may be interchangeably utilized in theself-aligning rotary electrical contact assembly shown in FIGS. 1-5.

FIG. 8 discloses an alternative brush member 70 which is adapted to bein slidable electrical contact with the longitudinal conductor 50 and inrotatable electrical contact with the arcuate conductor 38. This isaccomplished by having a first end 60 projecting into the longitudinalrecess 14 and two bent segments made in the wire such that oppositesurfaces 72 and 74 each tangentially contact the arcuate conductor 38 ofthe core member 16 and thus provide rotatable contact.

FIG. 9 discloses a brush assembly 80 which is similar to brush assembly58 in that a bent segment 62 is provided which rotatably contacts thearcuate conductor 38 in two places. An additional bent segment 82 hasbeen provided to equalize the load being placed upon longitudinalconductor 50 and the arcuate or slip ring conductor 38.

FIG. 110 discloses a brush member 86 which constitutes anotheralternative embodiment. Brush member 86 comprises a segmentally concavesegment 88 formed between the first end 60 of the brush member 86 andthe second end 90. By utilizing a concave segment 88, the brush assembly86 provides a load upon the arcuate conductor 38, 180 apart and,therefore, applies a more uniform lead to the core member 16.

FIG. 11 discloses still another alternative embodiment. However, it willbe readily recognized that the brush member 92 disclosed in FIGURE 11differs substantially from the previous brush members 58, 70, 80 and 86in that both ends 94 and 96 of the brush member 92 protrude into thelongitudinal recesses 98 provided in the housing member 99. In thisinstance, however, the longitudinal electrical conductor 100 is disposedin a pair of recesses 98 in the housing member 99 rather than in asingle recess 50 as shown in FIG. 2. The iongitudinal conductors 100 areinterconnected with each other to form a pair of longitudinal conductorsalong which the single brush 92 is in slidable contact therewith. Asbefore, the two ends of the conductor 100 are twisted together to form asingle lead 102.

It should be understood, of course, that the foregoing disclosurerelates only to preferred embodiments of the invention and that numerousmodifications or alterations maybe made therein without departing fromthe spirit and the scope of the invention as set forth in the appendedclaims.

What is claimed is:

l. A self-aligning rotary electrical contact assembly for concentricrelatively rotatable members comprising:

an annular recess in said first member and a linear recess disposedtransversely to said annular recess in said second member;

a first electrical conductor disposed within said annular recess formingan arcuate conducting element;

a second electrical conductor disposed within said linear recess; andbrush member disposed in said annular recess having a portion thereofprojecting into said linear recess wherein said brush member is inrotatable contact with said arcuate conducting element and is inslidable contact with said second electrical conductor thereby causingsaid brush member to be automatically positioned.

2. A self-aligning rotary electrical contact assembly comprising:

a cylindrical core member;

a housing member concentrically disposed in rotatable relation aroundsaid core member;

an annular recess in said core member;

a longitudinal recess in said housing member, said longitudinal recessbeing transverse to said annular recess;

a first electrical conductor disposed within said annular recess formingan arcuate conducting element;

a second electrical conductor longitudinally disposed within saidlongitudinal recess; and

a brush member disposed in said annular recess having a portion thereofprojecting into said longitudinal recess wherein said brush member is inrotatable contact with said arcuate conducting element and is inslidable contact with said second electrical conductor thereby causingsaid brush member to be automatically positioned in a planeperpendicular to the axis of said core member.

3. The apparatus of claim 2 wherein said brush member is compressedbetween said arcuate conducting element and said second electricalconductor wherein said compression causes a load on said core.

4. The apparatus of claim 2 further comprising an opening in said coremember adapted to receive each end of said first electrical conductorwhereby said ends of said first conductor are threaded into the interiorof said core member.

5. The apparatus of claim 2 further comprising an aperture in saidhousing member adapted to receive said first end of said secondelectrical conductor whereby said first end of said second electricalconductor is threaded through said aperture and wherein said first andsecond ends of said second electrical conductor are joined together,externally from said housing member thereby securing said secondelectrical conductor in said longitudinal recess.

6. The apparatus of claim 5 wherein a segment of said aperture is spacedapart from and parallel to said longitudinal recess.

7. The apparatus of claim 2 further comprising a second longitudinalrecess in said outer surface of said housing member adapted to receivesaid first and second ends of said second electrical conductor, whereinsaid first and second ends of said electrical conductor are joinedtogether, externally from said housing member thereby securing saidsecond electrical conductor in said longitudinal recess.

8. The apparatus of claim 2 wherein said brush member comprises:

a first end projecting into said longitudinal recess;

a second end; and

a bent segment formed between said first end and said second end, saidbent segment being in rotatable contact with said arcuate conductingelement.

9. The apparatus of claim 8 wherein the bent segment of said brushmember tangentially contacts said arcuate conducting element at twopoints.

10. The apparatus of claim 2 wherein said brush member comprises:

a first end projecting into said longitudinal recess;

a second end; and

a bent segment between said first end and said second end wherein afirst surface and a second surface of said bent segment each contactsaid arcuate conducting element.

111. The apparatus of claim 10 wherein said first and second surfaceseach tangentially contact said arcuate conducting element.

12. The apparatus of claim 2 wherein said brush member comprises:

a first end projecting into said longitudinal recess;

a second end; and

a segmentally concave segment formed between said first end and saidsecond, said concave segment being in rotatable contact with saidarcuate conducting element.

13. A self-aligning rotary electrical contact assembly for concentricrelatively rotatable members comprising:

a plurality of radially aligned, spaced annular recesses in said firstmember and a plurality of spaced linear recesses disposed transverselyto said annular recesses in said second member;

a first electrical conductor disposed within each of said annularrecesses forming a plurality of arcuate conducting elements;

a second electrical conductor linearly disposed within each of saidlinear recesses;

a brush member disposed in each of said annular recesses having aportion thereof projecting into a preselected one of said linearrecesses wherein each of said brush members is in rotatable contact withthe arcuate conducting element associated therewith and is in slidablecontact with said second electrical conductor associated therewiththereby causing each of said brush members to be automaticallypositioned.

14. A self-aligning rotary electrical contact assembly comprising:

a cylindrical core member;

a housing member concentrically disposed in rotatable relation aroundsaid core member;

a plurality of radially aligned, spaced annular recesses in the outersurface of said core member;

a plurality of spaced longitudinal recesses in the inner surface of saidhousing member;

a first electrical conductor disposed within each of said annularrecesses forming a plurality of arcuate conducting elements;

a second electrical conductor longitudinally disposed within each ofsaid longitudinal recesses; and

a brush member disposed in each of said annular recesses having aportion thereof projecting into a preselected one of said longitudinalrecesses wherein each of said brush members is in rotatable contact withthe arcuate conducting element associated therewith and is in slidablecontact with said second electrical conductor associated therewiththereby causing each of said brush members to be automaticallypositioned in a plane perpendicular to the axis of said core member.

15. The apparatus of claim 14 wherein each adjacent brush member isoriented such that said preselected longitudinal recess associated witheach of said brush members is different from said preselectedlongitudinal recess associated with said adjacent brush member, therebyangularly displacing said projecting portions of said adjacent brushmembers.

16. The apparatus of claim 15 wherein said angular displacement betweenadjacent brush members is approximately 90.

17. A self-aligning rotary electrical contact assembly comprising:

a cylindrical core member;

a housing member concentrically disposed in rotatable relation aroundsaid core member;

at least one annular recess in the outer surface of said core member;

at least one pair of spaced longitudinal recesses in the inner surfaceof said housing member;

a first electrical conductor disposed within each of said annularrecesses forming a plurality of arcuate conducting elements;

a second electrical conductor longitudinally disposed within each ofsaid pairs of longitudinal recesses;

a brush member disposed in each of said annular recesses having a firstend, a second end and a bent segment between said first and second ends,said first and second ends each projecting into said pair oflongitudinal recesses and are each in slidable contact with said secondelectrical conductor associated therewith and said bent segment being inrotatable contact with said arcuate conducting element thereby causingeach of said brush mem- W bers to be automatically positioned in a planeperpendicular to the axis of said core member.

18. The apparatus of claim 17 wherein each adjacent brush member isoriented such that said pair of longitudinal recesses associated witheach of said brush members is difierent from said pair of longitudinalrecesses associated with said adjacent brush member.

19. A method of assembling a self'aligning rotary contact includingconcentric relatively rotatable members comprising the steps of:

providing an annular recess in said first member;

forming an arcuate electrical conductor within said annular recess;

providing a linear recess transversely to said annular recess in saidsecond member; forming a linear electrical conductor within said linearrecesses;

inserting a brush member in said annular recess, said brush member beingin rotatable contact with said arcuate electrical conductor and having afirst end thereof extending beyond the periphery of said annular recess;and

inserting said first member into said second member and inserting saidfirst end of said brush member into said linear recesses wherein saidfirst end of said brush member is in slidable contact with said linearconductor and whereby said brush member is aligned in a positiondetermined solely by said position of said linear recess.

20. A method of assembling a self-aligning rotary contact assemblyincluding a cylindrical core member and a substantially cylindricalhousing member comprising the steps of:

providing a plurality of radially aligned, spaced annular recesses inthe outer surface of said core member; forming an arcuate electricalconductor within each of said annular recesses;

providing a plurality of spaced, longitudinal recesses in the innersurface of said housing member;

forming a longitudinal electrical conductor within each of saidlongitudinal recesses;

inserting a brush member in each of said annular recesses,

each of said brush members being in rotatable contact with said arcuateelectrical conductor associated therewith and having a first end thereofextending beyond the periphery of said annular recess;

inserting a portion of said core member into said housing member andinserting said first end of said first brush member into a first one ofsaid longitudinal recesses wherein said first end of said brush memberis in slidable contact with said longitudinal conductor associatedtherewith; and

continuing to insert said core member into said housing member andinserting said first end of said second brush member into a second oneof said longitudinal recesses in slidable contact with said longitudinalcontact associated therewith whereby each of said brush members isaligned in a position determined solely by said position of saidlongitudinal recesses and whereby each of said brush members ispositioned in a plane perpendicular to the axis of said core member.

t i it t i UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRE TION PatentNo. 3'652'97l Dated March 28,1'11972' Inventor) K'enly Co "Bugg Itiscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 1, line 41, change 'oontampla'te" to contemplate Column 1, line73, h n "element" -,to elements Column 5, line 25, change "lead" to loedColumn 6, line 40, after "wherein", change "the" to--said-.

Signed and sealed thi 's lQthof Se p temberi-l972.

Attest: V.

EDWARD mmmmcmin ,JR. ROBERT GO'ITSCHALK Attesting Officer: CommissionerofPatents FORM PC4050 f Q I USCOMM-DC 005764 08 (5 ".5. GOVERNMENTPRINYING OFFICE: "l9 O-JGG8SQ

1. A self-aligning rotary electrical contact assembly for concentricrelatively rotatable members comprising: an annular recess in said firstmember and a linear recess disposed transversely to said annular recessin said second member; a first electrical conductor disposed within saidannular recess forming an arcuate conducting element; a secondelectrical conductor disposed within said linear recess; and a brushmember disposed in said annular recess having a portion thereofprojecting into said linear recess wherein said brush member is inrotatable contact with said arcuate conducting element and is inslidable contact with said second electrical conductor thereby causingsaid brush member to be automatically positioned.
 2. A self-aligningrotary electrical contact assembly comprising: a cylindrical coremember; a housing member concentrically disposed in rotatable relationaround said core member; an annular recess in said core member; alongitudinal recess in said housing member, said longitudinal recessbeing transverse to said annular recess; a first electrical conductordisposed within said annular recess forming an arcuate conductingelement; a second electrical conductor longitudinally disposed withinsaid longitudinal recess; and a brush member disposed in said annularrecess having a portion thereof projecting into said longitudinal recesswherein said brush member is in rotatable contact with said arcuateconducting element and is in slidable contact with said secondelectrical conductor thereby causing said brush member to beautomatically positioned in a plane perpendicular to the axis of saidcore member.
 3. The apparatus of claim 2 wherein said brush member iscompressed between said arcuate conducting element and said secondelectrical conductor wherein said compression causes a load on saidcore.
 4. The apparatus of claim 2 further comprising an opening in saidcore member adapted to receive each end of said first electricalconductor whereby said ends of said first conductor are threaded intothe interior of said core member.
 5. The apparatus of claim 2 furthercomprising an aperture in said housing member adapted to receive saidfirst end of said second electrical conductor whereby said first end ofsaid second electrical conductor is threaded through said aperture andwherein said first and second ends of said second electrical conductorare joined together, externally from said housing member therebysecuring said second electrical conductor in said longitudinal recess.6. The apparatus of claim 5 wherein a segment of said aperture is spacedapart from and parallel to said longitudinal recess.
 7. The apparatus ofclaim 2 further comprising a second longitudinal recess in said outersurface of said housing member adapted to receive said first and secondends of said second electrical conductor, wherein said first and secondends of said electrical conductor are joined together, externally fromsaid housing member thereby securing said second electrical conductor insaid longitudinal recess.
 8. The apparatus of claim 2 wherein said brushmember comprises: a first end projecting into said longitudinal recess;a second end; and a bent segment formed between said first end and saidsecond end, said bent segment being in rotatable contact with saidarcuate conducting element.
 9. The apparatus of claim 8 wherein the bentsegment of said brush member tangentially contacts said arcuateconducting element at two points.
 10. The apparatus of claim 2 whereinsaid brush member comprises: a first end projecting into saidlongitudinal recess; A second end; and a bent segment between said firstend and said second end wherein a first surface and a second surface ofsaid bent segment each contact said arcuate conducting element.
 11. Theapparatus of claim 10 wherein said first and second surfaces eachtangentially contact said arcuate conducting element.
 12. The apparatusof claim 2 wherein said brush member comprises: a first end projectinginto said longitudinal recess; a second end; and a segmentally concavesegment formed between said first end and said second, said concavesegment being in rotatable contact with said arcuate conducting element.13. A self-aligning rotary electrical contact assembly for concentricrelatively rotatable members comprising: a plurality of radiallyaligned, spaced annular recesses in said first member and a plurality ofspaced linear recesses disposed transversely to said annular recesses insaid second member; a first electrical conductor disposed within each ofsaid annular recesses forming a plurality of arcuate conductingelements; a second electrical conductor linearly disposed within each ofsaid linear recesses; a brush member disposed in each of said annularrecesses having a portion thereof projecting into a preselected one ofsaid linear recesses wherein each of said brush members is in rotatablecontact with the arcuate conducting element associated therewith and isin slidable contact with said second electrical conductor associatedtherewith thereby causing each of said brush members to be automaticallypositioned.
 14. A self-aligning rotary electrical contact assemblycomprising: a cylindrical core member; a housing member concentricallydisposed in rotatable relation around said core member; a plurality ofradially aligned, spaced annular recesses in the outer surface of saidcore member; a plurality of spaced longitudinal recesses in the innersurface of said housing member; a first electrical conductor disposedwithin each of said annular recesses forming a plurality of arcuateconducting elements; a second electrical conductor longitudinallydisposed within each of said longitudinal recesses; and a brush memberdisposed in each of said annular recesses having a portion thereofprojecting into a preselected one of said longitudinal recesses whereineach of said brush members is in rotatable contact with the arcuateconducting element associated therewith and is in slidable contact withsaid second electrical conductor associated therewith thereby causingeach of said brush members to be automatically positioned in a planeperpendicular to the axis of said core member.
 15. The apparatus ofclaim 14 wherein each adjacent brush member is oriented such that saidpreselected longitudinal recess associated with each of said brushmembers is different from said preselected longitudinal recessassociated with said adjacent brush member, thereby angularly displacingsaid projecting portions of said adjacent brush members.
 16. Theapparatus of claim 15 wherein said angular displacement between adjacentbrush members is approximately 90*.
 17. A self-aligning rotaryelectrical contact assembly comprising: a cylindrical core member; ahousing member concentrically disposed in rotatable relation around saidcore member; at least one annular recess in the outer surface of saidcore member; at least one pair of spaced longitudinal recesses in theinner surface of said housing member; a first electrical conductordisposed within each of said annular recesses forming a plurality ofarcuate conducting elements; a second electrical conductorlongitudinally disposed within each of said pairs of longitudinalrecesses; a brush member disposed in each of said annular recesseshaving a first end, a second end and a bent segment between said firstand second ends, said first and second ends each projecting into saidpair of longitudinal recesSes and are each in slidable contact with saidsecond electrical conductor associated therewith and said bent segmentbeing in rotatable contact with said arcuate conducting element therebycausing each of said brush members to be automatically positioned in aplane perpendicular to the axis of said core member.
 18. The apparatusof claim 17 wherein each adjacent brush member is oriented such thatsaid pair of longitudinal recesses associated with each of said brushmembers is different from said pair of longitudinal recesses associatedwith said adjacent brush member.
 19. A method of assembling aself-aligning rotary contact including concentric relatively rotatablemembers comprising the steps of: providing an annular recess in saidfirst member; forming an arcuate electrical conductor within saidannular recess; providing a linear recess transversely to said annularrecess in said second member; forming a linear electrical conductorwithin said linear recesses; inserting a brush member in said annularrecess, said brush member being in rotatable contact with said arcuateelectrical conductor and having a first end thereof extending beyond theperiphery of said annular recess; and inserting said first member intosaid second member and inserting said first end of said brush memberinto said linear recesses wherein said first end of said brush member isin slidable contact with said linear conductor and whereby said brushmember is aligned in a position determined solely by said position ofsaid linear recess.
 20. A method of assembling a self-aligning rotarycontact assembly including a cylindrical core member and a substantiallycylindrical housing member comprising the steps of: providing aplurality of radially aligned, spaced annular recesses in the outersurface of said core member; forming an arcuate electrical conductorwithin each of said annular recesses; providing a plurality of spaced,longitudinal recesses in the inner surface of said housing member;forming a longitudinal electrical conductor within each of saidlongitudinal recesses; inserting a brush member in each of said annularrecesses, each of said brush members being in rotatable contact withsaid arcuate electrical conductor associated therewith and having afirst end thereof extending beyond the periphery of said annular recess;inserting a portion of said core member into said housing member andinserting said first end of said first brush member into a first one ofsaid longitudinal recesses wherein said first end of said brush memberis in slidable contact with said longitudinal conductor associatedtherewith; and continuing to insert said core member into said housingmember and inserting said first end of said second brush member into asecond one of said longitudinal recesses in slidable contact with saidlongitudinal contact associated therewith whereby each of said brushmembers is aligned in a position determined solely by said position ofsaid longitudinal recesses and whereby each of said brush members ispositioned in a plane perpendicular to the axis of said core member.